Armrest adjusting mechanism

Abstract

An adjusting mechanism for easily and simultaneously adjusting the height and the angular orientation of an armrest is provided. The adjusting mechanism includes a supporting sleeve connected at a lower end to a chair and an outer casing connected at an upper end to an armrest and put around the supporting sleeve. A joint pipe fixed in an upper part of the supporting sleeve includes a first half having multiple rows of locating holes and a second half having multiple horizontally spaced stop grooves. A bent control arm is disposed in the outer casing with an upper end projected from the outer casing to serve as a hand control and a lower end extended into the supporting sleeve. Upward pushing the hand control brings a locating means provided at the lower end of the control arm to disengage from the locating hole and a stop arm provided opposite to the locating means to elastically press against one stop groove, allowing the outer casing to freely move upward or downward and rotate relative to the supporting sleeve and thereby achieve adjustment of the armrest associated therewith.

What is claimed is: 
     
       1. An armrest adjusting mechanism, comprising a supporting sleeve, a lower end of which is mounted onto or connected to a chair or the like, and an outer casing, an upper end of which is connected to an armrest of the chair; said supporting sleeve being fixedly provided in an upper part with a round joint pipe having a proper length and consisting of two vertically extended curved halves, a first curved half of said joint pipe being provided with a plurality of rows of spaced locating through holes, and a second curved half of said joint pipe being provided at an inner surface with a plurality of horizontally spaced stop grooves of proper depth; and   said outer casing being put around said supporting sleeve and having an elbow-shaped control arm consisting of a horizontal part with an upward bend and a substantially straight vertical part positioned therein, a lower end of said vertical part of said control arm downwardly extending into a space between said two halves of said joint pipe, and said horizontal part of said control arm being supported in an opening near a top of said outer casing with a free end of said horizontal part extended from said opening to provide a hand control and said upward bend elastically and pivotally connected to said outer casing in said opening by means of two springs; said vertical part of said control arm being provided at the lower end with a locating means that radially projects from one side of said vertical part facing said first half of said joint pipe and has a profile suitable for easily engaging into each individual locating hole, said vertical part of said control arm being also provided at the lower end at another side opposite to said locating means with a stop arm that extends outward and downward from the lower end of said control arm to face toward said second curved half of said joint pipe; a distance by which said stop arm outward extends being so determined that when said locating means is disengaged from said locating holes, a free end of said stop arm would most preferably extend into and elastically press against one of said stop grooves;   whereby when said hand control extended from said outer casing is upwardly pushed, said lower end of said control arm is pivotally shifted away from said first half of said joint pipe, causing said locating means to disengage from said locating hole and thereby allowing said outer casing to be moved upward or downward or rotated relative to said supporting sleeve to a desired position, and when said hand control is released, said lower end of said control arm is pivotally shifted toward said first half of said joint pipe to cause said locating means to engage into said locating hole at a selected position and thereby easily complete adjustment of said armrest to a desired height and angle relative to said chair at one time.   
     
     
       2. An armrest adjusting mechanism as claimed in claim 1, wherein said hand control is preferably located at a position closely below said armrest, so that a user may easily access and upwardly push said hand control. 
     
     
       3. An armrest adjusting mechanism as claimed in claim 1, wherein said stop arm and said control arm are integrally and plastically molded during manufacture of said control arm so that said outward and downward extended stop arm is provided with sufficient toughness, and wherein said stop arm has a predetermined width and a curvature the same as that of said stop grooves, such that a contact area between said stop arm and each of said stop grooves is maximized. 
     
     
       4. An armrest adjusting mechanism as claimed in claim 1, wherein said locating holes are provided at outer peripheries with guiding bevel surfaces for said locating means to engage into said locating holes more easily. 
     
     
       5. An armrest adjusting mechanism as claimed in claim 1, wherein said stop grooves are densely arranged on said second half of said joint pipe at reduced spacing distance between any two of said stop grooves adjacent to each other.